Field of the Invention
The present invention relates to a seat mechanism, and more particularly to a seatback-seat linkage mechanism.
Related Prior Art
Most vehicle seats are designed in such a way that the angle of the seatback is adjustable, and in particular, there is a design that can adjust the seatback and the seat simultaneously. In the process of tilting the seatback, the seat will have a corresponding amount of displacement. The conventional seatback-seat linkage mechanism has various designs, and one of them is as shown in FIG. 1 and includes a first seatback unit 61, a first fixed seat 62, a first movable seat 63 and a first connecting rod assembly 64.
The first seatback unit 61 is connected to one end of the first fixed seat 62. The first connecting rod assembly 64 has two ends pivotally connected to the first seatback unit 61 and the first fixed seat 62, respectively. A pivot point 641 is disposed between the two ends of the first connecting rod assembly 64 to connect one end of the first movable seat 63. Therefore, when the user controls the first seatback unit 61 to tilt backward, the first movable seat 63 can be moved backward through the pivot point 641 of the first connecting rod assembly 64. In addition, another end of the first fixed seat 62 opposite to the end connected to the first seatback unit 61 is provided with a first seat pipe 621, and the first movable seat 63 has an engaging slot 631 formed at a lateral edge facing the first seat pipe 621. The first movable seat 63 moves until the first seat pipe 621 is engaged in the engaging slot 631.
Another design of the conventional seatback-seat linkage mechanism is as shown in FIG. 2, which includes: a second movable seat 71, a second connecting rod assembly 72 and two second seat pipes 73.
The second connecting rod assembly 72 has two ends pivotally connected to a second seatback unit 74 and the second movable seat 71, respectively. The second movable seat 71 is mounted on the second seat pipes 73, and has a side surface facing the second seat pipes 73 provided with two engaging protrusions 71A. Two sides of each of the engaging protrusions 71A are connected with an arc-shaped surface 71B, respectively. When the user controls the second seatback unit 74 to title backward, the second connecting rod assembly 72 will drivingly move the second movable seat 71, so that the second movable seat 71 will approach one end of the second seatback unit 74 while moving down along the curves of the arc-shaped surfaces 71B, so as to achieve the function of linkage mechanism.
Yet another design of the conventional seatback-seat linkage mechanism is as shown in FIG. 3, which includes: a third seatback unit 81, a third movable seat 82, a seat 83 and a plurality of bolts 84. The third movable seat 82 is provided with a plurality of slots 821. Each of the third seatback unit 81 and the third movable seat 82 is provided with two bolts 84 which are movably disposed in the respective slots 821. When the third seatback unit 81 tilts backward, it will move the third movable seat 82 via a third connecting rod assembly 85, so that the third movable seat 82 will be guided by the slots 821 to move backward and downward.
From the foregoing description, it can be known that the seatback-seat linkage mechanisms are often and mostly used in combination with the radian or the curves of the seat only, and its reliability and stability are slightly insufficient. In addition, although conventional seatback-seat linkage mechanism as shown in FIG. 3 is provided with the slots 821 and the bolts 84, the bolts 84 are disposed on and pivotally connected to the third seatback unit 81 and the third movable seat 82 by a plurality of sheet members. These conventional seatback-seat linkage mechanisms not only have a less stable structure, but also are vulnerable to damage.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.